Implementation of sliding mode control in DC microgrids

Upon the increasing implementation of direct current (DC) power sources, energy storages and loads in power systems, DC microgrids have drawn more attention from global stakeholders. Reliable operation of DC microgrids mainly depends on proper control method to cope with bus voltage variations due to renewable sources intermittency and load changes. The main objectives of the control method are to maintain the operating bus voltage and the power balance. This control method is applied in battery energy storage (BES) component. By charging and discharging power to and from BES the control objectives can be achieved. Sliding mode control (SMC) method is implemented because of its robustness for sudden variations of power sources and loads. SMC is also of fast response in dynamics. Washout filter is applied to minimize the transient response. DC microgrid model is developed in Matlab/Simulink simulation to verify the performance of SMC. The comparison between SMC and the conventional proportional-plus-integral (PI) control is also carried out in the analysis.